As far as I'm concerned the chances of infection from viruses and worms are minimal. For a start it is a service you pay for and this usually deters most baddies in the first place. For a second, viruses don't typically lurk in image files. When viruses do lurk in image files, they can only infect a computer with software security flaws. Ensuring you run a machine with all the latest Windows Updates and Patches is therefore paramount.

It is therefore quite safe to just download the files. If there is a virus in the file, your antivirus program will probably detect it before or whilst you are downloading, even the free ones such as AVG and Antivir. Then when downloaded, you can always scan them again. As long as you don't open them, there is practically very little risk.